Power drive for a movable closure with ball nut driven flexible cable

ABSTRACT

A power drive moves a movable closure between an open position and a closed position with respect to a portal defining a passage through a barrier. The power drive can include an elongated drive member connected to the movable closure and a ball nut drive assembly for selectively moving the drive member longitudinally to position the movable closure between the open position and the closed position with respect to the passage through the barrier. The barrier can define at least a portion of a stationary structure or a vehicle, where the passage allows access within the structure or the vehicle. The movable closure can include a sliding door, hatch, window, or roof panel. The elongated drive member can be a flexible, wire wound push/pull cable having at least one wire member helically wound in uniformly spaced turns around a core of the push/pull cable to form a screw member capable of being driven by operable engagement with the recirculating ball nut drive assembly.

RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No. 08/501,557 filed Jul. 12, 1995 for "Acceleration Reaction Clutch With Override Capability" and Attorney Docket No. AESI4440 (ITT-281-A) filed contemporaneously herewith for "Power Drive For A Movable Closure With Ball Nut Drive Screw" and Attorney Docket No. AESI4441 (ITT-282-A) filed contemporaneously herewith for "Power Striker With Inertially Activated Impact Cycle".

FIELD OF THE INVENTION

The present invention relates to a power drive system for driving a movable closure such as a sliding door, hatch or window in movement with respect to a portal defining a passage through a barrier between an open position and a closed position, and more particularly, to a ball nut drive unit for selectively applying linear movement to a drive member, such as a flexible push/pull cable.

BACKGROUND OF THE INVENTION

It is generally known to provide a power drive system for driving a sliding door in movement between an open position and a closed position, where the drive arrangement accommodates shifting between manual operation and positively driven powered operation of the door at any position along its path of movement while providing a control responsive to an overload to stop door movement in the event an object is trapped by the closing door. These types of power drive systems are especially well adapted for use in operating the sliding door of a van-type vehicle. Typically, a power drive system is capable of driving an output member coupled to the door to drive the door in either direction over a relatively long working stroke. The coupling between the output member and the door can take the form of a positive mechanical interconnection between the motor and the door operable in either direction of movement as required. Additional problems may be presented where the power drive system is to power the sliding door of a van-type vehicle over and above the foregoing considerations applicable to sliding doors in general.

The power drive system for a sliding door in a van-type vehicle application is conventionally mounted on either longitudinally extending side of the van and the system may be operated by control switches accessible from the driver's seat. However, there are many occasions where the driver may desire to open or close the door manually, such as when the driver is outside the van loading or unloading articles through the sliding door and the controls are out of reach. A positively mechanically linked connection between the door and the power source will interfere with manual operation of the door and may disturb a relationship between the door and drive relied on by the control system to sense the position of the door along its path of travel.

Translation of a vehicle door requires an efficient set of machine elements and clutches to allow the door to overhaul the system. Yet the driving system must drive efficiently and not offer a significant resistance when being overhauled. A soft coupling may be employed to assure system loads remain in the range of acceptable machine element loads. A ball nut is a highly efficient machine element when used with a ball screw. However, the ball screw is rigid and expensive when used in applications requiring significant travel.

SUMMARY OF THE INVENTION

The present invention employs a single, or multiple, lead flexible cable used in conjunction with the axial bearing supported ball nut to achieve low cost and flexible travel with high efficiency. An armature, or other motor, engages an overrunning clutch assembly driving the driving gear through a resilient coupling. The driving gear is engaged with a driven gear at any ear ratio "N". The driven gear may be molded over or formed on a single or multiple lead ball or roller nut. The thrust of the roller nut is absorbed by a roller or ball bearing, spindle, conrad, etc. pair. A driven member, such as a screw or flexible wire wound cable, defining a gear commercially available as TELEFLEX, HILEX, or SUHNER cable or the like, is routed through the recirculating ball or roller nut. The position of the gear/cable is monitored by the combination of a magnet and a magnetic sensor for position sensing using the magnetic Hall effect, alternatively, magneto resistive, optical, or other type of sensor may keep track of rotation in the engaged units. Inner and outer housings tie the unit to the end of a motor. This device is particularly well adapted for a sliding movable closure, such as a door, hatch, roof panel, window or the like, and may be used in numerous automotive and non-automotive applications.

The door drive system according to the present invention uses a push/pull cable connected at one end to the movable closure, such as a door, and guided in longitudinal movement within a guide track which extends parallel to the path of movement of the door along at least one edge of the portal or door opening. The cable is driven in longitudinal movement by a reversible electric motor controlled by an electronic control unit in a manner such that the door may be automatically stopped in response to sensing of an overload, such as the jamming of an object between the closing door and the door frame, or providing for express operation and cancellation.

A wire-like member is helically wound in uniformly spaced turns around the core of the push/pull cable preferably over its entire length to form a screw-like member having an exterior helical gear tooth or thread defining a single lead, double lead, triple lead or other multiple leads as desired for the particular application. The cables can be heat treated to embed the cables in the stranded internal wire cable as is conventional. A 45° lead is preferable with a lead angle in a range of between 20° and 70° inclusive. A ball nut drive means is rotatably mounted within a housing fixed to surrounding stationary structure or frame for engaging and selectively moving the push/pull cable longitudinally to position the movable closure between the open position and the closed position with respect to a portal defining a passage through a barrier, such as a wall, roof or the like of a vehicle or building. The flexible gear, such as a wire wound cable, is threaded through a recirculating ball nut drive assembly disposed within a housing for rotation in order to longitudinally drive the flexible gear in either longitudinal direction in response to rotation of the recirculating ball nut drive assembly with respect to the housing. The recirculating ball nut drive assembly includes a plurality of gear teeth formed on an external periphery thereof for intermeshing engagement with a driving gear. The driving gear is connected through a resilient rotational coupling to an overrunning clutch assembly. The drive shaft of a reversible electric motor is connected to the clutch assembly for driving the drive gear in either rotational direction to produce longitudinal movement of the flexible gear in either longitudinal direction.

Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:

FIG. 1 is a perspective view of a barrier, such as a wall of a van, with certain parts broken away, showing the general location of certain components of the present invention within a vehicle;

FIG. 2 is a perspective view of a portion of the interior of the van of FIG. 1 with certain parts broken away or omitted;

FIG. 3 is a cross-sectional view of a ball nut drive means according to the present invention;

FIG. 4 is a cross-sectional view of the power drive according to the present invention taken as shown in FIG. 3; and

FIG. 5 is a cross-sectional vie of an alternative power drive configuration according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIGS. 1 and 2, there is shown a barrier, such as a wall of a vehicle, such as a van V having a movable closure, such as a sliding door D located on at least one side of the vehicle. Vans using such sliding doors have been available for years and the structural arrangements by which the door is mounted on the vehicle for manual movement between the closed position shown in FIGS. 1 and 2 in which the door is sealingly seated in a door opening and an open position in which the door is disposed at the side of the van rearwardly of the door opening is well known. In the standard arrangement, the door is latched in its closed position, typically by mechanical latches 20 and 22 at the front and rear edges of the door, the latches being mechanically linked to a latch actuator 24 mounted within the door to be simultaneously released by manual actuation of appropriate door handles. In many cases, the rear latch 22 may include a power driven striker mechanism 25 which is latchingly engaged with the door as it approaches its closed position and is power driven to move the latched door to its fully closed position.

The present invention is directed to certain components of a power drive system by means of which a movable closure, such as a sliding door, hatch, roof panel, window or the like can be power driven in either direction between its open and closed positions. The power drive system includes a motor driven gearbox 30 which is selectively operable to drive an elongate drive member 34, such as a flexible push/pull cable, in forward and rearward sliding movement within a cable guide track designated generally 36 fixedly mounted with respect to a portal on the vehicle frame to extend along at least one edge of the door opening or passage along a path parallel to the path of movement of the door between its open and closed positions. One end of the drive member 34 is operably coupled to the movable closure at a conventional door mounting bracket 38 so that power driven movement of the drive member or cable 34 forwardly and rearwardly through the guide track 36 drives the door D between its open and closed position. The coupling arrangement between cable 34 and door D is such that initial movement of cable 34 in a door opening direction is transmitted to latch release mechanism 24 to release the door latches or an electro-mechanical actuator is implemented to open the door in response to a signal from the control unit 56.

The elongated drive member 34 extends forwardly of the vehicle from the front end of guide track 36, passes entirely through gearbox 30 and extends forwardly from the gearbox into a storage housing 32, the drive member 34 being fed into storage housing 32 during forward movement of drive member 34 and being withdrawn from housing 32 during rearward movement. Gearbox 30 and housing 32 may conveniently be mounted on the vehicle floor beneath at least one of the occupant's seat. The motor 40 which drives member 34 via gearbox 30 is a reversible motor controlled by appropriate directional switches 54 which may be mounted at least on the vehicle dash within reach of the driver's seat, the switches 54 being operatively connected to motor 40 via an electronic control unit 56. Parallel connected control switches may be mounted at other locations on the vehicle, if desired.

The employment of an electronic control unit enables the power drive for the door to be operated in a safe and efficient manner, as by providing the door with an anti-pinch capability by automatically stopping the drive if an object becomes trapped between the closing door and the door frame, providing for express operation and eliminating the need for limit switches to sense specific door positions. Electronic control units capable of being programmed to perform these, and similar functions, are well known and commercially available from a variety of sources.

Details of the motor driven gearbox 30 can best be seen in FIGS. 3-4. The reversible motor 40 is resiliently mounted with respect to the gearbox 30 with a shaft 46 projecting outwardly from the motor 40 into engagement with clutch means 52 for allowing the door to overhaul the power drive system during manual operation, and for transmitting rotary power through the clutch means 52 to drive the door between the open and closed positions during power operations. An example of a suitable clutch means 52, by way of example and not limitation, is disclosed and illustrated in U.S. patent application Ser. No. 08/501,557 filed Jul. 12, 1995, for "Acceleration Reaction Clutch With Override Capability", which is incorporated by reference herein.

An output shaft 42 is connected to the clutch means 52 for transferring rotary output power to a pinion gear or driving gear 58. The shaft 42 extends within a housing 44 and is supported for rotation by bearings 48 with respect to the housing 44. The shaft 42 is resiliently coupled to a hub 50 of the driving gear 58 for rotation therewith. The driving or pinion gear 58 includes a plurality of first gear teeth 60 intermeshingly engaged with a plurality of second gear teeth 62 connected to ball nut drive means 64. The ball nut drive means 64 is rotatably disposed within the housing 44 by bearings 66 for selectively moving the drive member 34 longitudinally to position the movable closure or sliding door between the open and closed positions with respect to the portal defining the passage through the barrier. The barrier is a construction forming an extended indefinite surface preventing or inhibiting the passage of persons or things, and can include a wall, ceiling, roof or cover for a stationary structure or a movable vehicle, such as the van V. The portal is structure defining an opening through the barrier for passage of persons or things, such as the framing of a door, window, hatch or roof panel opening. The movable closure is an obstructive structure whose presence in or before a passage bars traffic through the passage and is mounted to move in a regular, repetitive, predetermined path with respect to the portal so as to alternately open or close the passage, and can take the form of a hatch, a sliding window, a roof panel or a sliding door D. Linear movement motor means or motor driven gearbox 30 causes the drive element 34 to move in a substantially linear or uni-directional path which may be straight, curved, or tortuous. While the ball nut drive means 64 provides for reversing the direction of movement of the movable drive member 34, the drive member 34 is not pivoted substantially about the longitudinal axis of the elongated drive member 34 as the ball nut drive means 64 rotates with respect to the housing 44.

The drive member 34 preferably includes a screw-like member extending along at least a portion of a longitudinal length of the drive member cooperatively engageable with the ball nut drive means 64. The drive member 34 may be covered by a drive sheath 86 at least partially between gearbox 30 and the sliding door D. Preferably, the drive member 34 is a flexible push/pull cable having at least one wire-like member 68 helically wound in uniform spaced turns around a core member 70 over at least a portion of a longitudinal length of the cable 34 cooperatively engageable with the ball nut drive means 64 corresponding to a screw-like member portion of drive member 34. The screw-like member portion of drive member 34 can extend along a portion of a longitudinal length of the drive member 34, or along the entire longitudinal length of the drive member 34. The screw-like portion includes helical gear teeth, such as those formed by wire-like members 68 operably engageable with a plurality of balls 72 for driving the drive member 34 longitudinally as the ball nut drive means 64 rotates with respect to the housing 44 in response to rotary power supplied by motor 40 through clutch means 52 and pinion gear 58. The plurality of balls 72 are recirculated longitudinally with respect to the ball nut 74 of the drive means 64 through ball return passage 76 as the ball nut 74 rotates with respect to the housing 44 on bearings 66.

The ball nut 74 can be formed with an overmolded gear 78 having the plurality of second gear teeth 62 connected to the ball nut 74 for rotation therewith. Gear means, such as pinion gear 58, drives the gear 78 in rotation about a longitudinal axis of the drive member 34. The gear 78 and pinion gear 58 can be formed with any desirable gear ratio for the particular application. Clutch means 52 connected to the gear means 58 provides for overrunning with respect to the gear means 58 in response to manual manipulation of the movable closure, or for slipping in response to the movable closure contacting an obstruction prior to reaching the open or closed position. Storage means 32 houses at least a portion of the drive member 34 opposite from the movable closure with respect to the ball nut drive means 64.

Sensing means 80 is responsive to rotary movement of the ball nut drive means 64 for transmitting to the electronic control unit 56 a signal representative of the location of the door D along the fixed path. The sensing means 80 can include a magnet 82 connected to the ball nut 74 for rotation therewith and a magnetic sensor 84 connected to the housing 44 for sensing the position of the magnet 82 as it passes by the sensor during rotation for transmitting to the electronic control unit 56 a signal representative of the location of the door along the fixed path of travel between the open and closed positions during manual and powered operations.

Referring now to FIG. 5, the reversible motor 40 can have a hollow shaft 46 allowing passage of the drive member 34 through the shaft 46 and motor 40. The shaft 46 sheathes a portion of the drive member 34 passing therethrough, and is connected to the ball nut drive means 64. The shaft 46 can be directly connected to the ball nut 74, or can be connected through a clutch means 52 (not shown in FIG. 5). The drive member 34 can be a rigid screw-like member, or worm gear, or a flexible cable member having a flexible core 70 and at least one helically wound gear tooth 68 as previously described passing through the gear box 30 including the housing 44 and drive ball nut 74. The balls 72 within the ball nut 74 drivingly engage the gear tooth or teeth 68 of the drive member 34 to move the drive member 34 longitudinally in either direction. The drive member 34 can be sheathed along at least a portion of its longitudinal length. The balls 72 are recirculated through recirculating passageway 76. The ball nut drive means 64 is rotatably mounted on bearing 66 within the housing 44. This can permit free-wheeling of the ball nut 74 and connected shaft 46 in response to manual manipulation of the movable closure or sliding door D.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law. 

What is claimed is:
 1. A moveable closure and a power drive for accommodating manual and powered operation of said moveable closure between an open position and a closed position with respect to a portal defining a passage through a barrier, said power drive comprising:an elongate flexible drive member connectible to said moveable closure through a non-linear path, said flexible member including a push/pull cable having at least one wire member helically wound in uniformly longitudinally spaced turns around a flexible core member over at least a portion of a longitudinal length of said cable to define an unobstructed helical groove with side wall portions defining an unobstruted open area between adjacent helical windings and a bottom wall portion of the helical groove formed by said core member of said flexible drive member; and ball nut drive means having a plurality of recirculating balls operably engaged with said unobstructed helical groove and selectively moving said drive member longitudinally through said non-linear path in response to rotation of said ball nut drive means, and for selectively positioning said moveable closure in said open and closed positions with respect to said passage through said barrier.
 2. The power drive of claim 1 further comprising:reversible electric motor means operably connected to said elongate drive member for linearly moving said drive member in either longitudinal direction.
 3. The power drive of claim 2 further comprising:clutch means connected to said electric motor means for overrunning with respect to said motor means in response to manual manipulation of said moveable closure.
 4. The power drive of claim 2 wherein said ball nut drive means further comprises:a rotatable, recirculating ball nut operably engageable with said drive member; and said motor means for driving said ball nut in reversible rotation about a longitudinal axis of said drive member.
 5. The power drive of claim 1 in combination with a vehicle wherein said barrier defines at least a portion of said vehicle and said passage allows access within said vehicle.
 6. The power drive of claim 5 wherein said moveable closure is selected from a group including a sliding door, a hatch, a roof panel and a sliding window.
 7. The power drive of claim 1 further comprising:storage means for housing at least a portion of said drive member opposite of said moveable closure with respect to said ball nut drive means.
 8. A sliding door system accommodating manual operation and powered operation of a sliding door in forward and rearward movement along a fixed path between an open position and a closed position, said system comprising:an elongate flexible drive member having first and second ends spaced from one another, said first end coupled to said door for longitudinal forward and rearward movement with said door through a non-linear path, said flexible member including a push/pull cable having at least one wire member helically wound in uniformly longitudinally spaced turns around a flexible core member over at least a portion of a longitudinal length of said cable to define an unobstructed helical groove with side wall portions defining an unobstructed open area between adjacent helical windings and a bottom wall portion of the helical groove formed by said core member of said flexible drive member; and ball nut drive means having a plurality of recirculating balls operably engaged with said unobstructed helical groove and positively mechanically engaged with said drive member for rotation coordinated with longitudinal forward and rearward movement of said drive member.
 9. The sliding door system of claim 8 further comprising:a variable speed, reversible, electric motor means having a rotary output shaft for powering movement of said door.
 10. The sliding door system of claim 9 further comprising:clutch means for positively mechanically coupling said output shaft to said ball nut drive means in response to rotation of said output shaft and for accommodating free rotation of said ball nut drive means relative to said output shaft for manual operation of said door.
 11. The sliding door system of claim 10 further comprising:control means for selectively operating said motor and including an electronic control unit responsive to a signal representative of the location of said door along said fixed path to perform selected door control functions when said door is at selected locations along said fixed path.
 12. The sliding door system of claim 11 further comprising:sensing means responsive to rotary movement of said ball nut drive means for transmitting to said electronic control unit a signal representative of the location of said door along said fixed path.
 13. The sliding door system of claim 8 wherein said ball nut drive means further comprises:a recirculating ball nut operably engageable with said drive member; and means for driving said recirculating ball nut in rotation about a longitudinal axis of said drive member.
 14. The sliding door system of claim 8 wherein said door defines a portal with respect to a vehicle and allows access within said vehicle when said door is in said open position.
 15. The sliding door system of claim 8 further comprising:storage means for housing at least a portion of said drive member opposite from said sliding door with respect to said ball nut drive means.
 16. In a combination of a sliding door mounted on at least one side of a vehicle for sliding movement forwardly and rearwardly of the vehicle between an open position and a closed position and a power drive system for moving said sliding door, said system including reversible power drive means operable when actuated to selectively drive said door in opening or closing movement, the improvement comprising:an elongate flexible drive member coupled to said door along a non-linear fixed path for longitudinal forward and rearward movement with said door, said drive member including a flexible push/pull cable having at least one wire member helically wound in uniformly longitudinally spaced turns around a core member offer at least a portion of a longitudinal length of said cable to define an unobstructed helical groove with side wall portions defining an unobstructed open area between adjacent helical windings and a bottom wall portion of the helical groove formed by said core member of said flexible drive member; recirculating ball nut drive means having a plurality of recirculating balls operably engaged with said unobstructed helical groove and positively mechanically engaged with said drive member for rotation coordinated with longitudinal forward and rearward movement of said drive member, wherein said recirculating ball nut drive means includes a recirculating ball nut having a plurality of gear teeth formed on an external periphery thereof for rotation therewith, said cable extending longitudinally sufficiently to be cooperatively engageable with said ball nut drive means; a variable speed, reversible, electric motor means having a rotary output shaft for powering movement of said door; gear means connected to said rotary output shaft and intermeshing with said gear teeth of said recirculating ball nut for driving said recirculating ball nut in rotation about a longitudinal axis of said drive member; clutch means for positively mechanically coupling said output shaft to said ball nut drive means in response to rotation of said output shaft and for accommodating free rotation of said ball nut drive means relative to said output shaft for manual operation of said door; control means for selectively operating said motor means and including an electronic control unit responsive to a signal representative of the location of said door along said fixed path to perform selected door control functions when said door is at selected locations along said fixed path; and sensing means responsive to rotary movement of said recirculating ball nut drive means for transmitting to said electronic control unit a signal representative of the location of said door along said fixed path.
 17. In combination, a closure moveable with respect to a portal defining a passage through a barrier and a power drive for moving said moveable closure between an open position and a closed position along a non-linear path, said power drive comprising:an elongate, flexible drive member connectible to said moveable closure through said non-linear path, said flexible drive member including a push/pull cable having at least one wire member helically wound in uniformly longitudinally spaced turns around a flexible core member over at least a portion of a longitudinal length of said cable to define an unobstructed helical groove with side wall portions defining an unobstructed open area between adjacent helical windings and a bottom wall portion of the helical groove formed by the core member of said flexible drive member; and ball nut drive means having a plurality of recirculating balls selectively moving said drive member longitudinally for positioning said moveable closure between said open and closed positions with respect to said passage through said barrier.
 18. The power drive of claim 17 further comprising:reversible electric motor means operably connected to said elongate drive member for linearly moving said drive member in either longitudinal direction.
 19. The power drive of claim 18 further comprising:clutch means connected to said electric motor means for overrunning with respect to said motor means in response to manual manipulation of said moveable closure.
 20. The power drive of claim 18 wherein said ball nut drive means further comprises:a rotatable, recirculating ball nut having a plurality of recirculating balls operably engageable with said unobstructed helical groove of said flexible drive member; and said motor means for driving said ball nut in reversible rotation about a longitudinal axis of said drive member.
 21. The power drive of claim 17 wherein said drive member further comprises a flexible push/pull cable having at least one wire member helically wound in uniformly longitudinally spaced turns around a core member over at least a portion of a longitudinal length of said cable cooperatively engageable with said ball nut drive means.
 22. The power drive of claim 17 wherein said drive member further comprises a screw member extending along at least a portion of a longitudinal length of said drive member cooperatively engageable with said ball nut drive means.
 23. The power drive of claim 17 wherein said moveable closure is selected from a group including a sliding door, a hatch, a roof panel and a sliding window.
 24. The power drive of claim 17 further comprising:storage means for housing at least a portion of said drive member opposite of said moveable closure with respect to said ball nut drive means. 